1. Field of the Invention
The present invention relates to the sequential passage of a known electrical current through a series of items of varying electrical resistance, and in particular to the passage of current through fowl with the purpose of killing or of stunning the fowl.
2. Related Background Art
There are various regulations aimed at minimizing pain or distress of fowl being slaughtered for human consumption. One method of meeting the regulations involves the use of electric shocks for killing the fowl or for stunning the fowl prior to slaughter. Although this specification relates to apparatus which might be used for killing fowl as well as to apparatus for stunning fowl, for convenience only the latter will be referred to hereafter. The conventional method of effecting this uses a moving shackle train from which the fowl are suspended head down so that the heads are passed through a water bath, the train and water bath having electrical connections such that an electrical current passes through the fowl and stuns them. Conventionally the train and water bath have a constant voltage applied across them. However it has been found in practice that the resistance of individual fowl varies considerably. Also the effective resistance can be affected by adjacent fowl coming into contact. As a result the current passing through the fowl varies considerably, and it appears that a significant number of fowl are only partially stunned.
Whilst one method of ensuring proper stunning of all fowl is to apply a voltage high enough to ensure a sufficient current through the most resistive fowl this results in unnecessary expense and also to high currents through less resistive fowl which can, in some circumstances, have deleterious effects.